Ultra-low Contrast Strategy for Routine Coronary Procedures via Distal Transradial Access: Real-World Experience With Consecutive All-Comers Patients From the DISTRACTION Registry

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J INVASIVE CARDIOL 2024. doi:10.25270/jic/24.00276. Epub November 15, 2024.

Objectives. The association of contrast volume to the risk of contrast-related acute kidney injury (CR-AKI) appears to have resulted in a change in daily practice toward using lower contrast volume for all patients. Distal transradial access (dTRA) has advantages in terms of faster haemostasis and lower rates of proximal radial artery occlusion. The present study aimed to describe the authors’ experience with the combination of ultra-low contrast (ULC) strategy and dTRA for routine coronary procedures in a real-world and broad population of all-comers patients.

Methods. Of 6852 patients consecutively included into the DISTRACTION registry from February 2019 to July 2024, successful ULC coronary procedures via dTRA were achieved in 4328 (63.2%). Related data were retrospectively assessed.  

Results. Most patients were male with acute coronary syndromes, and the mean patient age was 63.6 ± 15 years. Access-site crossover occurred in only 3% of cases. Right dTRA was the most frequently utilized primary access site, and was almost always performed with standard 6-French radial sheaths. ULC strategy was feasible for every scenario, with the overall contrast volume less than or equal to 40 mL for 96.4% of all patients, regardless of coronary bypass surgical grafts presence, percutaneous coronary intervention immediately following coronary angiography, anatomical or clinical complexity, or unavailability of intravascular ultrasound guidance. Neither major complications nor major adverse cerebrovascular and cardiac events directly related to dTRA were recorded. The rates of CR-AKI were very low (1.1%).

Conclusions. When performed by experienced operators, the minimalist combination of ULC strategy and dTRA for routine coronary procedures, regardless of baseline creatinine clearance, appears to be safe and feasible.

Defined as the development of AKI following contrast media administration in the absence of an alternative etiology,¹ contrast-related acute kidney injury (CR-AKI) is associated with increased morbidity, mortality, and health care costs.^2,3 The only evidence-based strategies that have been effective at reducing the incidence of CR-AKI are the use of low-osmolar or iso-osmolar contrast media, the minimization of contrast volume (CV), and assuring appropriate hydration.^2,4,5

Since the awareness of CV’s association to CR-AKI risk has increased, a change in daily practice toward using lower doses of contrast media for all patients has been observed.⁶ Additionally, select centers have reported on their experiences performing percutaneous coronary intervention (PCI) with ultra-low CV, particularly in patients who are at high risk.⁴ However, the prevalence and clinical impact of this practice in the broader interventional community remain unknown.

The current available evidence supports proximal transradial access (pTRA) over transfemoral access in order to decrease the risk of AKI.^2,7Distal transradial access (dTRA), in comparison to pTRA, has advantages in terms of expedited haemostasis and lower rates of proximal radial artery occlusion (RAO)^8,9 and, since February 2019, has become our first choice for coronary procedures (Figure).^10-14

To the best of our knowledge, the association of ultra-low contrast (ULC) strategy and dTRA for coronary procedures has not been assessed to date. Therefore, the present study aimed to describe the authors’ experience with the combination of ULC strategy and dTRA for routine coronary angiography (CAG) and/or PCI in a real-world and broad population of all-comers patients.

Definitions

The estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) Creatinine Equation (2021) using the most recent preprocedural serum creatinine level as baseline.¹⁵ CR-AKI was defined as the development of AKI following contrast media administration in the absence of an alternative aetiology. While there are several definitions for CR-AKI, one of the most commonly adopted is the Kidney Disease Improving Global Outcomes definition, which defines it as an increase in serum creatinine by at least 0.3 mg/dL within 48 hours after contrast exposure, or an increase to at least 50% within 7 days.¹⁶ CR-AKI requiring dialysis was defined as the new need for in-hospital renal replacement therapy.

Study population

Consecutive patients who underwent CAG and/or PCI via dTRA at 2 tertiary hospitals (Hospital Regional do Vale do Paraíba, Taubaté, São Paulo, Brazil and Hospital São Paulo, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil) were enrolled in the DISTRACTION (DIStal TRAnsradial access as default approach for Coronary angiography and intervenTIONs) registry (ensaiosclinicos.gov.br Identifier: RBR-7nzxkm) from February 2019 to July 2024 (N = 6852). The enrolment inclusion criterion was the presence of any (even weak) palpable pulses at both anatomical snuffbox and wrist. Notably, patients with unstable hemodynamic conditions were included. The Research Ethics Committee of the Hospital São Paulo, Escola Paulista de Medicina, Universidade Federal de São Paulo (protocol 4.071.731, CAAE 30384020.5.0000.5505) approved the study, and informed consent was given as a prerequisite before enrolling each subject in this registry and for anonymous use of data for retrospective evaluation. Follow-up was performed via phone interview, review of hospital records, or outpatient visit. All patients signed an informed consent, approved by the local ethics committee, for procedural data collection and for the anonymous use of data for retrospective evaluation.

ULC strategy

The ULC strategy for coronary procedures was implemented by a single experienced operator (MDO) between February 2019 and July 2024, regardless of clinical setting and baseline eGFR. Table 1 summarizes the basilar principles and strategies for contrast volume reduction during CAG and/or PCI. No restriction was applied with regard to anatomical characteristics (eg, chronic total occlusion, left main, bifurcations, calcification, etc.) or procedural factors (eg, need for rotational atherectomy). ULC CAG and/or PCI protocol success was defined as achieving technical success while maintaining a CV/eGFR of 1 or less.

dTRA protocol

The protocol adopted for CAG and/or PCI via dTRA has been previously described in detail elsewhere.^10-12

Intravascular imaging

Table 2 encompasses the technical description of intravascular ultrasound (IVUS) guidance to minimize CV during PCI. Intravascular imaging plays a major role for ULC PCI and should be performed at every key procedural step. In this study, IVUS was performed with 40 MHz or 60 MHz (High-Definition) Opticross catheters (Boston Scientific) and the Polaris workstation (Boston Scientific) utilizing 0.5 mm/s automatic and additional manual pullbacks.

Statistical analysis

Continuous variables were presented as mean ± standard deviation and the Mann-Whitney U-test was used for comparisons. Categorical variables were presented as frequency (percentages) and compared using the Chi-square test or Fisher’s exact test, as appropriate. For all tests, a P-value of less than 0.05 was considered significant. Statistical analysis was performed using Research Electronic Data Capture (REDCap) version 14.6.0 (Vanderbilt University).

Out of 6852 patients included into the DISTRACTION registry, successful ULC CAG and/or PCI was achieved in 4328 (63.2%). Table 3 summarizes the baseline demographic features, and Tables 4, 5 and 6 show the procedural characteristics, the total CV according to specific procedures, and any procedural-related complications, respectively.

The mean patient age was 63.6 ± 15 years old. Most of the patients were male (65%) and had hypertension (76.7%) and acute coronary syndromes (53.5%); overall, 903 (20.9%) patients had ST-segment elevation myocardial infarction (STEMI). One hundred thirty-seven (3.2%) presented to the catheterization laboratory in cardiogenic shock and, even so, were submitted to CAG and/or PCI via dTRA. Of note, 40.7% of patients had diabetes and 12.9% had previous ipsilateral dTRA sheath insertion. According to the CKD EPI calculator,¹⁵ the mean baseline eGFR was 75 ± 24.5 mL/min/1.73m², 288 (6.7%) patients had an eGFR of at least 15 (eGFR < 60 mL/min/1.73m²), and 81 (1.9%) patients were already under dialysis (eGFR < 15mL/min/1.73m²) (Table 3). The most frequent primary access site was the right dTRA (77%), followed by the redo right dTRA (12.5%) and the left dTRA (9%). Standard 6-French radial sheaths and regular radial compression devices were used for most patients (94.1% and 95.2%, respectively) (Table 4).   

The most prevalent target coronary territory was the left anterior descending artery (and its branches) (29.2%), followed by the right coronary artery (19.2%) and the left circumflex artery (13.5%) (Table 4). The incidence of access-site crossovers (failed wiring and sheath insertion despite successful distal radial artery puncture) was only 3%, 74% of which were successfully executed via pTRA or contralateral dTRA. Successful final dTRA sheath insertion was achieved in 4212 (97.3%) of the 4328 patients.

By strictly following the basilar principles depicted in Table 1, ULC strategy was feasible for every different scenario, regardless of the presence of coronary bypass surgical grafts, PCI immediately following CAG, anatomical or clinical complexity, or the unavailability of IVUS-guidance (Table 5).

There were no major complications or major adverse cerebrovascular and cardiac events recorded that were directly related to dTRA, and there were no differences at occurrence of bleeding or any access site-related complications observed among the multiple haemostasis strategies. Also, no hand/thumb dysfunction after any procedure was documented. Despite not being fully reliable because of the absence of systematic ultrasound evaluation, distal radial artery pulses were palpable in the vast majority of the patients after haemostasis and at hospital discharge.¹⁷ The rates of CR-AKI were very low (Table 6).

The present study evaluated our experience with both dTRA and ULC for routine coronary procedures in a real-world and broad population of all-comers patients, encompassing all presentations of coronary artery disease. Data were obtained from the DISTRACTION registry, the first Brazilian registry to assess dTRA as the standard for routine CAG and/or PCI.

Total CV is proportional to the risk of CR-AKI, and, as the degree of CKD increases, the deleterious effects of CV become more pronounced. A CV/eGFR greater than 2 has been identified as an independent predictor of CR-AKI in patients with an eGFR of less than 30 mL/min/1.73m².⁴ In such patients, a CV/eGFR less than 1 is ideal for minimizing the risk of CR-AKI^4,18 and has thus been identified as a distinctive characteristic of ULC PCI protocols.²

ULC has being increasingly adopted by interventionalists because it is associated with a meaningful reduction in the risk of AKI, especially among high-risk patients. For those undergoing invasive cardiac procedures, eGFR is routinely calculated and CV/eGFR, a simple tool that is being increasingly incorporated into clinical practice, might guide the total CV. The risk of CR-AKI and need for dialysis is markedly increased when the CV/eGFR exceeds 3.⁴

Beyond simply avoiding high CV, many groups have focused on performing PCI with exceedingly low CV. Kane et al¹⁹ described their experience with ULC in a cohort of 185 patients with nondialysis-dependent CKD, demonstrating the feasibility of such an approach in a larger cohort and the associated reduction in the incidence of AKI with lower CV. In an attempt to minimize CV to less than 15 mL, Nayak at al reported their strategy of routine biplane angiography, IVUS guidance, “dry” fluoroscopic imaging, and careful minimization of the contrast injection in the patients with the highest risk.²⁰

The MOZART (Minimizing cOntrast utiliZation with IVUS guidance in coRonary angioplasTy) trial validated the benefits of using IVUS guidance to minimize CV:²¹ the authors randomized 83 patients to angiography-guided PCI or IVUS-guided PCI, and operators were strongly encouraged to follow the aforementioned contrast-sparing measures (Tables 1, 2) in both study arms. The total CV was 20 mL (IQR: 12.5-30 mL) in the IVUS-guided group vs 64.5 mL (IQR: 42.8-97 mL) in the angiography-guided group (P < .001). There were no differences in CR-AKI rates, even though the study was not powered for such an outcome, and the baseline eGFR was preserved in the majority of patients, which is identical to the present study. Since the vast majority of patients included in the present study were assisted by the national public health system, IVUS availability was limited because of reimbursement constraints. Notwithstanding, ULC PCI strategy was quite feasible and safe.

Compared with transfemoral access, pTRA is associated with lower rates of major bleeding and, consequently, hemodynamic instability during PCI. By avoiding manipulation of the abdominal aorta, pTRA can also reduce atheromatous debris embolization to renal arteries.² In a 2016 meta-analysis comparing vascular access site and risk of CR-AKI in 26 185 patients undergoing PCI, pTRA was associated with a lower risk of CR-AKI (odds-ratio [OR]: 0.51; 95% CI, 0.39-0.67; P < .0001).⁷ In the MATRIX-Access (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of Angiox) trial,²² 8210 patients with acute coronary syndromes were randomized to transradial or transfemoral PCI, with less AKI in the transradial arm (15.4% vs 17.4%; OR: 0.87; 95% CI, 0.77-0.98; P = .02). Patients at the highest risk for AKI had a positive interaction, including those with reduced eGFR, advanced Killip class, or high Mehran score, and with whom a greater benefit of pTRA was associated. Therefore, the available evidence supports pTRA over transfemoral access, when feasible, to decrease the risk of AKI.² However, to date, there are no available data addressing dTRA.

Over the last 7 years, dTRA has been increasingly incorporated by many interventionalists around the world. The most recent systematic review and meta-analysis of 28 studies comparing dTRA and pTRA for coronary procedures included a total of 9151 patients (dTRA: 4474; pTRA: 4677). Compared with pTRA, dTRA was associated with shorter haemostasis time (mean difference [MD]: -32.49 [95% CI, -65.53, -2.46], P < .00001) and reduced incidences of RAO (risk ratio [RR]: 0.38 [95% CI, 0.25, 0.57], P < .00001), bleeding (RR: 0.44 [95% CI, 0.22, 0.86], P = .02), and pseudoaneurysm (RR: 0.41 [95% CI, 0.18, 0.99], P = .05). In turn, the drawbacks of dTRA were increased access time (MD: 0.31 [95% CI, -0.09, 0.71], P < .00001) and higher crossover rates (RR: 2.75 [95% CI, 1.70, 4.44], P < .00001). The KODRA (Korean Prospective Registry for Evaluating the Safety and Efficacy of Distal Radial Approach) trial,²³ a prospective multicenter registry, evaluated 4977 patients. The rates of distal and proximal RAO by palpation at 1-month follow-up were both 0.8%. Access-site crossover (6.7%) was more than 2-fold higher than in the present study (3%).

Limitations

This was a retrospective analysis of procedures performed by 1 experienced interventional cardiologist. Thus, these results may not be extrapolated and generalized to other centers and to interventional cardiologists who are unfamiliar with both ULC strategy and dTRA technique. Additionally, the absence of a control group restrains further suppositions. Neither fluoroscopy and procedure times nor dTRA puncture and cannulation attempts and times were systematically recorded. The absence of routine post-procedure Doppler ultrasound evaluation might have underestimated vascular complications rates, even with the presence of proximal and distal radial artery pulses after haemostasis and at discharge, However, the performance of a successful dTRA approach without ultrasound guidance might help to raise awareness about this novel technique.

The minimalist combination of ULC strategy and dTRA for routine coronary angiography and/or interventions, regardless of baseline eGFR, when performed by experienced operators, appears to be safe and feasible. Further randomized and controlled trials are needed to reassure these findings. 

Marcos Danillo Oliveira, MD, MSc; Adriano Caixeta, MD, PhD

From the Department of Interventional Cardiology, Hospital Universitário I, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.

Disclosures: The authors report no financial relationships or conflicts of interest regarding the content herein.

Acknowledgments: The authors acknowledge Samantha Propper, RCIS, BS, MBA (@dontmissabeat, orcid.org/0009-0007-5530-0851) for her special and kind execution of the Figure.

Address for correspondence: Adriano Caixeta, MD, PhD, Department of Interventional Cardiology, Hospital São Paulo, Escola Paulista de Medicina, UNIFESP. Napoleão de Barros, nº 715 - Vila Clementino, São Paulo 04024-002, Brazil. Email: acaixeta@me.com